linux/fs/jfs/jfs_mount.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *   Copyright (C) International Business Machines Corp., 2000-2004
 */

/*
 * Module: jfs_mount.c
 *
 * note: file system in transition to aggregate/fileset:
 *
 * file system mount is interpreted as the mount of aggregate,
 * if not already mounted, and mount of the single/only fileset in
 * the aggregate;
 *
 * a file system/aggregate is represented by an internal inode
 * (aka mount inode) initialized with aggregate superblock;
 * each vfs represents a fileset, and points to its "fileset inode
 * allocation map inode" (aka fileset inode):
 * (an aggregate itself is structured recursively as a filset:
 * an internal vfs is constructed and points to its "fileset inode
 * allocation map inode" (aka aggregate inode) where each inode
 * represents a fileset inode) so that inode number is mapped to
 * on-disk inode in uniform way at both aggregate and fileset level;
 *
 * each vnode/inode of a fileset is linked to its vfs (to facilitate
 * per fileset inode operations, e.g., unmount of a fileset, etc.);
 * each inode points to the mount inode (to facilitate access to
 * per aggregate information, e.g., block size, etc.) as well as
 * its file set inode.
 *
 *   aggregate
 *   ipmnt
 *   mntvfs -> fileset ipimap+ -> aggregate ipbmap -> aggregate ipaimap;
 *             fileset vfs     -> vp(1) <-> ... <-> vp(n) <->vproot;
 */

#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/blkdev.h>
#include <linux/log2.h>

#include "jfs_incore.h"
#include "jfs_filsys.h"
#include "jfs_superblock.h"
#include "jfs_dmap.h"
#include "jfs_imap.h"
#include "jfs_metapage.h"
#include "jfs_debug.h"


/*
 * forward references
 */
static int chkSuper(struct super_block *);
static int logMOUNT(struct super_block *sb);

/*
 * NAME:	jfs_mount(sb)
 *
 * FUNCTION:	vfs_mount()
 *
 * PARAMETER:	sb	- super block
 *
 * RETURN:	-EBUSY	- device already mounted or open for write
 *		-EBUSY	- cvrdvp already mounted;
 *		-EBUSY	- mount table full
 *		-ENOTDIR- cvrdvp not directory on a device mount
 *		-ENXIO	- device open failure
 */
int jfs_mount(struct super_block *sb)
{ … }

/*
 * NAME:	jfs_mount_rw(sb, remount)
 *
 * FUNCTION:	Completes read-write mount, or remounts read-only volume
 *		as read-write
 */
int jfs_mount_rw(struct super_block *sb, int remount)
{ … }

/*
 *	chkSuper()
 *
 * validate the superblock of the file system to be mounted and
 * get the file system parameters.
 *
 * returns
 *	0 with fragsize set if check successful
 *	error code if not successful
 */
static int chkSuper(struct super_block *sb)
{ … }


/*
 *	updateSuper()
 *
 * update synchronously superblock if it is mounted read-write.
 */
int updateSuper(struct super_block *sb, uint state)
{ … }


/*
 *	readSuper()
 *
 * read superblock by raw sector address
 */
int readSuper(struct super_block *sb, struct buffer_head **bpp)
{ … }


/*
 *	logMOUNT()
 *
 * function: write a MOUNT log record for file system.
 *
 * MOUNT record keeps logredo() from processing log records
 * for this file system past this point in log.
 * it is harmless if mount fails.
 *
 * note: MOUNT record is at aggregate level, not at fileset level,
 * since log records of previous mounts of a fileset
 * (e.g., AFTER record of extent allocation) have to be processed
 * to update block allocation map at aggregate level.
 */
static int logMOUNT(struct super_block *sb)
{ … }